Body implantable electrical stimulators are well known to the prior art, the most common being the cardiac pacemaker. Typically, such stimulators are formed of a separable lead and signal generator with provision being made to electrically and mechanically interconnect the lead and generator to complete the stimulator unit.
Prior art signal generators have been formed by molding their components, including the mechanical and electrical connectors for the lead, in a matrix of encapsulating material which supports the components and shields them from the body environment. Typically, the encapsulating material is an epoxy which is clear and allows a viewing of the interconnection between the lead and generator.
More recently, the electrical components forming the signal generator have been housed within a rigid enclosure formed of a plurality of preformed members which are typically welded together to complete the enclosure. The interconnection between the generator and the lead, when it is desired that these members be separable, occurs outside of such an enclosure. While it is possible to mold the interconnect assembly from epoxy, such a process diminishes one of the benefits from the use of a preformed enclosure--elimination of the epoxy encapsulation process. Thus, a preformed interconnect assembly, formed by injection molding, for example, which may be reliably secured to a preformed enclosure housing the generator components would greatly facilitate assembly of the stimulator. The amount of handling would be reduced with the remaining handling being easier to perform than an epoxy molding process. However, available materials for injection molding which are also suitable for use within the body environment are opaque, thus preventing the viewing of the interconnection between the lead and generator that is possible in a molded epoxy.